A Runtime Safety Enforcement Approach by Monitoring and Adaptation

The use of models and formal analysis techniques at runtime is fundamental to address safety assurance during the system operational stage, when all relevant uncertainties and unknowns can be resolved. This paper presents a novel approach to runtime safety enforcement of software systems based on the MAPE-K control loop architecture for system monitoring and control, and on the Abstract State Machine as runtime model representing the enforcement strategy aimed at preserving or eventually restoring safety. The enforcer software is designed as an autonomic manager that wraps around the software system to monitor and manage unsafe system changes using probing and effecting interfaces provided by the system, so realising grey-box safety enforcement. The proposed approach is supported by a component framework that is here illustrated by means of a case study in the health-care domain.